Auger spectroscopy analysis of magnesian calcite overgrowths precipitated from seawater and solutions of similar composition

Mucci, Alfonso; Morse, John W.; Kaminsky, M.

doi:10.2475/ajs.285.4.289

Cited by 52 publications

(30 citation statements)

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“…The observed increase of Sr/Ca in O. universa with [CO 3 2Ϫ ] in our experiments is consistent with a calcification rate control over Sr/Ca. In contrast, Mg incorporation into inorganic calcite appears to be unaffected by calcification rate over a range of saturation states (Mucci and Morse, 1983;Mucci et al, 1985).…”

Section: Implications For the Incorporation Of U Into Calcitementioning

confidence: 67%

Effects of seawater carbonate ion concentration and temperature on shell U, Mg, and Sr in cultured planktonic foraminifera

Russell

Hönisch

Spero

et al. 2004

Geochimica et Cosmochimica Acta

393

521

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Section: Implications For the Incorporation Of U Into Calcitementioning

confidence: 67%

Effects of seawater carbonate ion concentration and temperature on shell U, Mg, and Sr in cultured planktonic foraminifera

Russell

Hönisch

Spero

et al. 2004

Geochimica et Cosmochimica Acta

393

521

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“…To put this another way, for a given set of temperature, pressure, and solution composition conditions, only a single value of the MgCO 3 content of calcite can be in equilibrium with a solution of a given magnesium to calcium ion activity ratio. Based on numerous precipitation experiments, in seawater where the magnesium to calcium activity ratio is $5, the equilibrium mol% MgCO 3 in calcite is about 8 ± 1 (e.g., Berner, 1978;Mucci and Morse, 1984;Morse and Mucci, 1984;Mucci et al, 1985;Zhong and Mucci, 1989;Hartley and Mucci, 1996;Ohde et al, 2005). Despite the fact that seawater carbonate cements form generally in compositionally modified seawater, this clearly contrasts with the dominant Mg-calcite cement composition of $12-13 mol% MgCO 3 (Garrels and Wollast, 1978;Videtich, 1985; Fig.…”

Section: General Considerationsmentioning

confidence: 94%

Initial responses of carbonate-rich shelf sediments to rising atmospheric pCO2 and “ocean acidification”: Role of high Mg-calcites

Morse

Andersson

Mackenzie

2006

Geochimica et Cosmochimica Acta

293

318

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“…For instance, Mucci et al (1985) found that Mg 311 partitioning remained unaffected in experiments, in which the precipitation rate was 312 varied by 12 orders of magnitude. 313…”

mentioning

confidence: 99%

Calcium carbonate veins in ocean crust record a threefold increase of seawater Mg/Ca in the past 30 million years

Rausch

Böhm

Bach

et al. 2013

Earth and Planetary Science Letters

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Chemical (Sr, Mg) and isotopic (δ18O, 87Sr/86Sr) compositions of calcium carbonate veins (CCV) in the oceanic basement were determined to reconstruct changes in Sr/Ca and Mg/Ca of seawater in the Cenozoic. We examined CCV from ten basement drill sites in the Atlantic and Pacific, ranging in age between 165 and 2.3 Ma. Six of these sites are from cold ridge flanks in basement <46 Ma, which provide direct information about seawater composition. CCV of these young sites were dated, using the Sr isotopic evolution of seawater. For the other sites, temperature-corrections were applied to correct for seawater-basement exchange processes. The combined data show that a period of constant/low Sr/Ca (4.46 -6.22 mmol/mol) and Mg/Ca (1.12 -2.03 mol/mol) between 165 and 30 Ma was followed by a steady increase in Mg/Ca ratios by a factor of three to modern ocean composition. Mg/Ca -Sr/Ca relations suggest that variations in hydrothermal fluxes and riverine input are likely causes driving the seawater compositional changes. However, additional forcing may be involved in explaining the timing and magnitude of changes. A plausible scenario is intensified carbonate production due to increased alkalinity input to the oceans from silicate weathering, which in turn is a result of subduction-zone recycling of CO2 from pelagic carbonate formed after the Cretaceous slow-down in ocean crust production rate. veins (CCV) in the oceanic basement were determined to reconstruct changes in Sr/Ca 20 and Mg/Ca of seawater in the Cenozoic. We examined CCV from ten basement drill 21 sites in the Atlantic and Pacific, ranging in age between 165 and 2.3 Ma. Six of these 22 sites are from cold ridge flanks in basement <46 Ma, which provide direct information 23 about seawater composition. CCV of these young sites were dated, using the Sr 24 isotopic evolution of seawater. For the other sites, temperature-corrections were 25 applied to correct for seawater-basement exchange processes. The combined data 26 Calcium carbonate veins in ocean crustshow that a period of constant/low Sr/Ca (4.46 -6.22 mmol/mol) and Mg/Ca (1.12 -27 2.03 mol/mol) between 165 and 30 Ma was followed by a steady increase in Mg/Ca 28 ratios by a factor of three to modern ocean composition. Mg/Ca -Sr/Ca relations 29 suggest that variations in hydrothermal fluxes and riverine input are likely causes 30 driving the seawater compositional changes. However, additional forcing may be 31 involved in explaining the timing and magnitude of changes. A plausible scenario is 32 intensified carbonate production due to increased alkalinity input to the oceans from 33 silicate weathering, which in turn is a result of subduction-zone recycling of CO 2 from 34 pelagic carbonate formed after the Cretaceous slow-down in ocean crust production 35 rate. 36 37 KEYWORDS 38 seawater evolution; mid-ocean ridges; hydrothermal circulation; carbonate veins 39 40 INTRODUCTION 41Circulation of seawater through the flanks of mid-ocean ridges has profound 42 effects on the chemistry of both seawater a...

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Auger spectroscopy analysis of magnesian calcite overgrowths precipitated from seawater and solutions of similar composition

Cited by 52 publications

References 0 publications

Effects of seawater carbonate ion concentration and temperature on shell U, Mg, and Sr in cultured planktonic foraminifera

Effects of seawater carbonate ion concentration and temperature on shell U, Mg, and Sr in cultured planktonic foraminifera

Initial responses of carbonate-rich shelf sediments to rising atmospheric pCO2 and “ocean acidification”: Role of high Mg-calcites

Calcium carbonate veins in ocean crust record a threefold increase of seawater Mg/Ca in the past 30 million years

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